Electric-arc lamp.



No.1663,698. Patented 055.11, I900.

J. H. HALLBERG.

ELEcTmc ARC LAMP.

(Application mad July 16, 1598.)

sebum-sum 2.

(No Model.)

THE NORRlS PEYEHS co Mom-uwov \MSHINGTON mV 0 Patented Dec. ll, I900.

J; H. HALLBERG.

ELECTRIC ARC LAMP.

(Application filed July 16, 189B.) gllo Model.) 3 SheatsSheet 3.

ma NORMS PETERS co. FHDTO-UTHO" WASHINGTON, n c.

UNITED STATES PATENT @FFIQE.

JOSEF HENRY I-IALLBERG, OF PEABODY, MASSACHUSETTS, ASSIGNOR TO THE STANDARD THERMOMETER AND ELECTRIC COMPANY, OF SAME PLACE.

ELECTRIC-ARC LAM P.

SPECIFICATION forming part of Letters Patent N 0. 663,698, dated December 11, 1900; Application filed July 16,1898. Serial No. 686,10fl. (N model.)

To (all whmrt 126 may concern: shown, but as broad enough in scope to in- Be it known that I, JOSEF HENRY I'IALL- clude the embodimentin any suitable and de- BERG, a subject of the King of Sweden and sired apparatus of the various features which Norway, residing at Peabody, in the county will be hereinafter fully illustrated and de- 55 of Essex and State of Massachusetts, have inscribed in the drawings and specificatiomand vented an Improvement in Electric Lamps, set forth in the claims. of which the following description, in connec- In the drawings, Figure 1 is a view in front tion with the accompanying drawings, is a elevation of an inclosed-arc lamp in the specification, like reference characters on the construction of which various features of my 60 1o drawings representing like parts. invention have been embodied, the globe and This invention has for its primary object cover of the lamp being shown in vertical the rectification in arc-lamps of certain desection, while parts are broken away in places Iiciencies the existence whereof has hindered to reveal more clearly the construction of the the utilization upon circuits bearing the alcentral portion of the lam p. Fig. 2 is a hori- 65 ternating current of this type of lampa use zontal section on the line 00 m, Fig. 1, looking which for many reasons would grow rapidly from top to bottom. Fig. 3 is a side elevain favor were it not for the lack of the imtion of the governing magnet or solenoid and provements hereinafter disclosed. the adjacent parts of its support, and Fig. 4:

Such is the nature of these improvements is a plan view of the solenoid. Fig. 5 is a 70 that while chiefly important in their contrivertical sectional detail of the dash-pot. Fig. bution to the production of a successful lamp 6 is a vertical side elevation of the inner globe for alternating currents their embodiment in and its support,partly in section,looking from arc-lamps generically is attended by a reright to left on the liney y, Fig. 1. Fig. 7is markable increase in efficiency. a vertical sectional detail on the line .0 w, 75 Briefly stated, a more perfect control and Fig. 6, showing the upper-carbon contact deregulation of the carbons has been effected vice in its lowered position. Fig. 8 is a plan by novelty of construction in the governingview of the latch or seat for the bottom earmagnet audits cooperating parts. Almost perbon and inner globe, and Fig. 9 is a view in feet noiselessness has been achieved, first, by side elevation of one of the nuts by which the 8o the improved form of magnet suppressing the latch is retained in operative position. Fig. chief source of vibration; again, by the pro- 10 is a plan view of the cover-top with switch vision of vibration-absorbing construction, and rlieostat for use when it is desired to and, further, bya novel mode of suspension utilize the lamp with both direct and alterwhereby the lamp is isolated from resonators nating currents. Fig. 11 is a diagrammatic S5 of any description. The initial cost of the view of a modified arrangement for the same lamp and its weight have been cut down by purpose, and Fig. 12 shows a modified form simplicity of design and the use of few parts, of solenoid to be described later. and in operating expenses an even more evi- Before entering upon a description of the dent reduction has been effected by provision various features of my invention I will indi o for increased facility in trimming and cleancate'iirst the general operation of the lamp ing, with devices enabling the trimmer to deselected for illustration and description as a termine visually and at a distance the conditypical and convenient embodiment of those tion of the carbons, obviating intimate exfeatures. amination of thelamp, which is often situated The electrical current derived from any 95 inconvenientlyforsuchinspection. Finally, suitable source (not shown) is led through I provide for the first time a lamp which may the double binding-post a a connection 10, be used without alteration or adjustment. switch S, connection to, double binding-post uponcircuits bearing alteratingordirectcnra a and connection to to the solenoid or rents. magnet M, thence by the con nection 10 bind- 100 Accordingly my invention is to be considing-post a, and collar p to the novel stationercd not as limited to the exact construction ary central post P, within which is free to move the carbon C, the latter deriving current from the post through the rider or contact member R (see Fig. 7) and in turn delivering the current through the arc to the carbon C. The carbon 0 is seated in a re ceptacle D, which conducts the current to a latch or seat E, supported by hangers F F, through the former of which the current passes to a binding-post (0 having a connection 1.0 with the double binding-post a a, constituting the other terminal of the lamp. The entrance of the current is accompanied by energization of the solenoid M, which attracts the armature N, and drawing it down thereby through the medium of the feed-leverH, clutch-rod K, and clutch K raises the carbon C, striking the arc, the uniformity of which latter is maintained thereafter by theresponse of the core N to the magnetic influence of the current acting through the solenoid M. With the knowledge of this mode of operation gathered readily from the foregoing brief description it will be easy to understand the novel technical effect gained by my improvements-an effect which begins to manifest itself at the initial movement of the carbon or upper electrode in striking the arc, since the upper electrode is raised steadily, slowly, and gradually from the lower carbon or electrode, with no suggestion of the chattering or noisy series of jerks which in such lamps prior to my invention has attended or constituted the operation of striking the are. This novel steadiness and silence so characteristic in the formation of the are by lamps in which my improved construction is embodied will be found to continue througlr out each period during which the lamp is energized and has been attained largely by the novel type of solenoid provided by me for this very purpose. ltis recognized generally that to adapt a lamp of this type for use with alternating currents of relatively low frequency a large amount of resistance must be arranged in circuit, and it is recognized equally that it would be desirable to confine this resistance within the limits of a single coil; but a coil of sufficient dimensions has been found impracticable, because subject to the evils attendant upon heating effects of the current.

The use of iron about the coil has increased its tendency to heat and added otherwise to its defects without increasing its efficiency to a compensating degree, so that in practice it has been the custom to introduce an extra resistance-coil into the circuit. With such an arrangement, however, the initial influx of current into the magnet-solenoid exerts too rapidly its influence upon the core, yanks tho clutch-lever, and breaks the are before it is fairly formed, so that with a repetition of these yanks or jerks the carbons chatter violently and annoyingly for a perceptible time before the arc is set.

My improved solenoid is characterized by a separation from each other of its constituent coils, either the helices or, if desired, the individual convolutions, accomplished in any convenient manner and provided for in the instance illustrated in Figs. 1 and at by the introduction of separating devices on, in the contour, number, and situation of which considerable variation will be found permissible, while in Fig. 12 the separation of the helices and suppression of the bad effects of heating is accomplished even more effectively by the interposition of asbestos or an equivalent heat-su p pressing m edium m B y separating the coils heating effects may be so obviated that the size of the solenoid and its consequent resistance to the initial influx of current may be increased far beyond that found practicable hitherto, and the initial magnetic effect upon the core will be delayed and steadied, as already noted.

Exterior ventilation of the solenoid may be, and 1. referal')ly is, provided for by isolation from adjacent mechanism so far as practicable, and this I have carried out in the construction of the novel supporting means illustrated, to the exclusive use of which construction 1 am not bound, however. In the instance illusfrated this support is derived from a shelf or member 1), of suitable contour, carried by the central post P in any suitable manner, as by an insulating-collar 2/, provided, preferably, with adjusting means 1/, the solenoid being in this instance shown as secured to the shelf by a suitable clamp 1, the contour of which may be varied, as desired or found suitable. This is shown as comprising a broad base 2, having a central aperture 3 opposite a similar aperture 1) in the shelf and the central aperture in of the solenoid to promote ventilation, and upright risers at, with arms, offsets, or holding means 5, provided, preferably, with fastening devices 6, between which and the solenoid may be interposed, if desired, wear-plates or the like 7 and cushioning material 8, preferably of an insulating nature, as asbestos, used also at 9, preferably, and covering as little of the solenoid as possible with efficiency in order to promote ventilation, for which battens 12 may be added also. The layer 9 should have a ventilating-hole, as also the layer 13 when such an additional cushioning layer is used as is desirable.

The armature N may be of any suitable shape and material; but I prefer to make it cylindrical of soft iron with a lillingor core of laminated iron n, as wires, (see Fig. 3,) and I have found it desirable to interpose a spring 20 to take up vibrations between it and the lever H, with suitable adjusting means 7L h, the lever H having also, if desired, regulating or balancing means 7L2 lbs of well-known orsuitable form. The lever H is carried by the central post P by suitable means, shown in this instance as a pivot 13 in a bracketarm p on a bracket p mounted on and preferably insulated from the collar 1), and adjacent the point of pivotal support, as at It,

the lever passes around the post P and is extended at its beyond the latter to receive a connection with the upright clutch-rod K and preferably a connection with a suitable dash-pot B. The latter will preferably be of the improved construction I have illustrated in Fig. 5, in which a plunger b with air-packing grooves 17, is supported in upright position to receive a cylindrical shell 19 hung by an adjustable link with fastening means b b from the lever H. The plunger (7 is preferably secured, as by a base Z) and screw Z1 to the shelf 19, and the shell b has vent-s b operative normally upon descent of the shell to allow the carbon C to fall quickly, but closed by a paper washer b operated bysuction, aided, preferably, by a weight 5 to close the holes and retard upward movement of the carbon C.

The clutch-rod K has preferably an insulating and adjusting joint is and a clutch K, both of well-known or suitable form, and I provide, preferably,a vibration-absorbing device to take up any vibrations inseparable from the use of the alternating current and escaping the various vibration-deadening devices, to which reference has been made already. This comprises a spring if, interposed between the clutch-arm k extended beyond the rod K for the purpose, and a support t, carried adjustably by the clutch-rod K. In practice I find that this device prevents effectually any joggling down of the carbon in the clutch, so often resulting in burning out the solenoid when older types of these lamps are used in places subject to mechanical jaras, for example, on the posts to which the trolley-wire of electric railways is attached. As the carbons are consumed the arc lengthens, its resistance increases, and the amperage in the solenoid decreases, releasing the armature, which rises under the drag set up by the Weight of the clutch, its rod, and the carbon, and the latter is permited to descend, approaching the lower carbon until, through the decreased length and resitsance of the are, an amperage is obtained in the solenoid sufficient to again exert a restraining tendency on the armature N,cheeking the carbon. Here again the effect of my improvements in the solenoid is manifest, inasmuch as the relatively large coil once saturated with the current presents a greater sensitiveness to variations of current strength than does a smaller coil, either when the latter is alone or when hampered by the influence of an extra coil. Not only does this sensitiveness make for greater steadiness of the are, but it enables me to maintain an are within two or three volts of the point at which the arc breaks n11- der normal conditions, instead of setting the mechanism to act atseveral volts under that point. Those skilled in the art will understand readily that thereby l secure a longer arc,brighter and more extended illumination, and less shadow than can be attained with the lower voltagenvhich prior makers have not dared to exceed, through fear of inability on the part of their solenoids to respond promptly to a sudden accession of amperage following the passing of an irregularity in the carbons, which has tem porarily raised the voltage and caused the arc to shorten. Frequently this slowness to respond permits overload and burning out of the solenoid, with other damage to the lamp,and at least an annoying flickering of the light attends the advent of each impurity as the carbons are consumed.

Not only does the elimination of the extra resistance-coil effect an obvious reduction in expense, but an advantage far from least among those attained is the suppression of a noiseproducing factor, since each coil adds its quota to the vibration set up in the lamp by the on rrent, especially an alternating cu rrent.

I have already referred to the use of layers 8 and 9 of asbestos or similar sound-deadening material between the magnet-coil M and its support, and I now call attention to the fact that the coil is more or less flexibly sup ported by the clamprisers 4 and pass on to one of the features of my invention by which the very important requisite of noiselessness is chiefly furthered.

Heretofore it. has been the custom, so far asI am aware universal, to suspend arc-la m ps directly by some rigid portion of their structure and to attach the cover thereto without regard to its quality as a resonator, so that through the rigid structure of the lamp each vibration was transmitted to the lamp'cover and to the ceiling, 850., and thence in exaggerated degree to the air of the room. I have made a complete reversal of this practice, furnishing the cover with the means for suspension from ceiling or the like and supporting the structure of the lamp proper from the cover, interposing, however, between the two sound-deadening means, so that such vibrations as may escape to the lamp skeleton from the solenoid through the layers 8 and .J or their equivalent will be taken up before they can reach the resonating surfaces of the cover and ceiling. This I believe to be new,broadly, and hence do not restrict myself to the particular construction illustrated, wherein the shelfp presents an extension or member 2), shown as annular, covered with a spring or springy jacket p of felt or the like, to rest upon suitable projections (17, preferably screws, extended inwardly from the cover A, other projections,as the brackets aibeing provided, preferably, to steady the ring and limit its entrance within the cover.

A hanger A, of any well-known orsuitable form, may be provided, if desired, at the top (0 and if the latter is of metal insulatingbushings ca a should be provided for the binding-posts a a, respectively.

The form of cover A and globe A may be varied, as desiredand found suitable, and any suitable means of supporting the latter may a see,

be adopted, thumb-screws a constituting one convenient form of such means.

Passing now to the carbon supporting or trimming mechanism, (best seen in Figs. 1 and 6,) abundant novelty will be found in the few light parts of its compact construction, comprising as essentials only a head V, hangers F F, a swinging seat or latch E, and receptacle D. Any suitable means to connect the latch or seat E with the hangers F F may be utilized, and as one form the nuts ff, engaging threads on the lower ends of the hang ers, have been found convenient, especially when the seat takes the form of the latch illustrated and best seen in Fig. 8, having an aperture 6 at one end to permit the passage of one hanger, about which the latch can be rotated without the necessity for entire removal, a slot 6, preferably curved, serving at the other end of the latch to permit the entrance laterally of the other hanger as the latch swings around into closed position, a similar medial slot 6 being provided, preferably, to receive the foot of the receptacle D of suitable contour to cooperate with the enlarged and countersunk inner end of said slot. To trim the lamp, the nuts ff are lowered and the latch swung around from under the receptacle D, when the latter will come out in the hand, bringing with it the lower carbon C, to hold which firmly in the receptacle fastening means cl are provided, preferably, while the inner globe A merely rests snugly, but freely, at its lower end on a shoulder (1 of the receptacle, which may, and preferably does, have a seat washer or gasket 61 and a retaining-flange d At its upper end the inner globe is seated in a similar manner against the head V, which preferably has an annular depression or seat o and gasket or washer '0 also. Coaxial with this depression and within the same extends downwardly a boss 72 having a central aperture to permit passage of the carbon or upper electrode 0, this aperture being enlarged to receive the clutch K, which is seated at times against the shoulder o A ring or ferrule 0 serves the double function of holding the washer c in place and supporting an annular disk or gas-check 12 preferably of lava or other heatresisting and insulating material, suit-ably secured to the ring, as by an apertured screw cap or rim c and forming, with the ring 12 and shoulder c, a gas-chamber c Above the head a crown '0 connects with the post P in suitable manner, as by a thread 71 to derive support therefrom and is apertured, as at o to give access to the upper carbon 0, while in the arms n v are held the upper ends of the hangers FF, insulated by bushings 0 11 a suitable annular reflector F being mounted, preferably, above the arc and supported in suitable manner, as by screw-collars f f on the hangers F F. In trimming, the latch having been swung away and the receptacle D, with carbon 0, having been removed, the inner globe will come away freely in the hand of the operator, ready for washing in hydrofluoric acid if need be, since it is without attached metal parts, so that no time will be lost in cleaning it. The upper carbon will then fall down until the rider R (see Fig. 7) rests againstthe clutch K, (see Fig. 6,) through which the rider cannot pass, normally preventing the upper carbon from falling out. Then the operator will pull the carbon out, grasp the rider through the head-aperture e", and insert a new carbon, and after the new carbon has been pushed up within the post Pthe inner globe A lower carbon C, and receptacle D may all be emplaced at once, the latch E swung around, the nuts ff'tightened up,and the operation of trimming will have been accomplished.

The small size of the hangers F F, insulated from the head at v 42 and of the receptacle D and seat or latch E is worthy of remark, as entirely unprecedented, but no lack of security has been experienced in their use largely on account of the novel and rigid central post P.

To aid in retaining the latch in closed position, I prefer to make use of a countersink in the latch, (shown in dotted lines at 0 Fig. 8,) into which countersink enters the beveled endf" of the nutf. (See Fig. 9.)

Reverting to the rider or sliding contact R, (see Fig. 7,) this may be varied in form without departing from the spirit of my invention; but I have illustrated one form which has shown itself capable of extended use, its simplicity ofstructure leaving little opening for breakdowns or failure to operate properly. The form of rider illustrated comprises a cylindrical tube of resilient material fitting loosely within the post P and split throughout a considerable portion of its length to form jaws r r, whichengage and grasp the head of the carbon C with sufficient force to prevent displacement by shock or otherwise accidentally. This split may be on one or bothsides, and preferably is enlarged at one or more points, as at 0' T to augment resili ency of the jaws, the lower aperture serving the additional function of means to give the operator a better grip either with his fingers or with a pencil or the like if the carbon and rider be heated.

To insure contact with the walls of the post P, some form of current-collecting device 0' is used, preferably, and I have shown as one form aspring or springs secured by suitable fastening means r to the body of the rider and extended beyond the walls thereof to contact yieldingly with the walls of the post P, the two springs in the instance illustrated being bent back upon themselves at r in position to contact with each other, thus deriving mutual support with enhanced resiliency and conductivity. As one means to protect these devices from injury, the walls of the rider may be extended above the devices and l l l l l l slotted or otherwise apertured, as at W, to permit access of the devices to the walls of the post.

An important feature of my invention is the provision of means to indicate visually to the operator standing at a distance the condition of the carbon, and as I believe myself to be the first to provide such means I do not limit myself to the exact form shown, which consists simply of a small incandescent lamp L, situated at any convenient portion of the arc-lamp, as on a support 0 adjacent an aperture 66 in the cover, through which the light of the lamp when energized will be visible. A conductor 10 taps the circuit at a convenient point, as at the bindingpost a, and another conductor '10 leads to a point adjacent the carbon, where is arranged a circuit-closer comprising a stationary, but preferably adjustable, member adapted to be engaged by a cooperating member movable with and controlled by the carbon, the latter member consisting most conveniently of the rider R itself, as indicated in Fig. 7. In this instance the other member Z of the circuit-closer is carried by the crown-shoulder 12 through the medium of a projection Z ,i11- sulated at Z from the shoulder and having an adjustable collar Z which presentsthe member Z toward and in position to be engaged by the rider R. Upon such engagement a circuit in shunt with the arc is completed through the member Z, projection Z, binding-post Z, conductor to, (see Fig. 1,) lamp L, and conductor r0 back into the circuit of the arc-lamp itself. This indicating means may be set by adjustment of the collar l in this instance to operate when the carbons have yet to burn, say, fifteen hours, and if the lamps are installed by the hundred in some stores the trimmer need only Walk across the front of the store and glance back at the lamps to determine by the glow of the incandescent lamps which of the arc-lamps are in need of attention. By this provision not only the time of the trimmer, so often wasted in useless climbingof ladders to inspect the lamps, is saved, but the annoyance of his presence in the confined space of the store or the like place is obviated, to the great relief of the user.

I have called attention already to the capability possessed by arc-lamps embodying my improvements for use on circuits bearing alternating currents or direct currents without change, alteration, or adj ustment of the lamp, and I have shown, diagrammatically, in Fig. 12 connections convenient for use in a situation where access is had to circuits bearing, respectively, the types of current mentioned, that lettered A O supplying the alternating current and that lettered D C the direct current,

L designates the lamp, from the terminals a" a of which run conductors Z Z respectively, to the middle terminals Z Z of a cirseaees cui t-controller, indicated as a six-pole doubleknife switch. having opposite pairs 1" and I Z of terminals receiving, respectively, the alternating-current and the direet-curre11t leads, the latter having the usual rheostatR included in its circuit. hen the handle S of the switch is in its upper position, as indicated, the alternating current may pass in at the terminal I, thence through the left-hand switch-lever to the middle pole l and along the conductor to the lamp, returning through the lampterminal a, conductor Z poles I I and intermediate switch lever to the other alternatingcurrent lead. A simple throw of the switch-handle S brings the switch -levers down to the terminals Z i cutting in the direct current in a manner precisely similar to that just detailed.

In Fig. 11 I have shown a plan view of the cover-top illustrated in Fig. 1, with the con trolling-switch and rheostat mounted in combination thereon, the parts indicated, diagrammatically, in Fig. 12 being shown in detail, but no difference existing in the opera tion, which I will not repeat, referring only to the construction of the rheostat illustated, a form convenient, but not essential. To the terminal Z of the switch a flexible, preferably insulated, conductor 7. is attached at one end, the other end of the conductor being free to move adjacent the coils of a resistancehelix 9' )referably composed of bare wire supported above and insulated from the cover-top a by suitable means, as the wellknown screw-knob insulators r illustrated. At 1' a binding-post or other suitable means is provided to permit connection of a direct current lead to the resistance, and I have shown the flexible connection Z as provided with means to effect detachably a union with the resistance at any desired point, one convenient form of such means comprising a clamp r secured by a set-screwr and having preferably another set-screw r to enable its jaws r to be attached firmly to the coil selected. As a single instance of the type of sit-nation in which this combination may be employed to advantage, I may mention a shop having a direct-current circuit energized by its own dynamo during the daytime, but dead at night, while the alternating current of a nearby streetcircuit is available at night, there being frequent occasion forillumination in parts of the shop after the power has shut down or perhaps broken down.

Obviously enough'to be able by the simple turn of a switch to utilize the street-current in a lamp already at hand is more than desirable, and this capability exists in arc-lam ps for the first time, so far as I am aware, by virtue of my improvements.

Having described my invention thus fully, I do not limit myself to the exact construction shown and described, since the same may be varied in many respects without departing from the spirit of my invention; but

That which 1 claim, and upon which I desire to secure protection, is-

1. .he combination with alamp of the class described, its cover-top and terminals, of a sixpole double-knife switch mounted on said top and having its middle pair of poles con nected respectively with said lam p-terminals, its pair of poles at one end adapted to receive the leads of a circuit bearing the alternating current, and its other pair of end poles adapted to receive, one pole a lead of a circuit bearing the diiect current, and the other pole a flexible conductor provided near its free end with a clamp, and adapted to serve as the movable member of a rheostat which includes a coil of bare resistance-wire, mounted on knob-insulators extended above said cover-top, and presentingits convolutions in position to be grasped by said conductorclamp, at different points.

2. A vibration-absorbing support for the magnets of electric-arc lamps, comprising a shelf upon which said magnet is seated; and a clamp having a broad base traversing said shelf on the side opposite said magnet, said clamp being provided with risers extended from said base along said magnet lengthwise and with retainingarms to hold the other end of said magnet.

3. A vibration-absorbing support for the magnets of electric-arc lamps, comprising a shelf upon which said magnet is seated; and a clamp having a broad base traversing said shelf on the side opposite said magnet, said clamp being provided with risers extended from said base along said magnet lengthwise and with retaining-arms to hold the other end of said magnet, and fastening means intermediate said arms and clamp.

4:. A vibrationabsorbing support for the magnets of electricarc lamps, comprising a shelf upon which said magnet is seated; and a clamp having a broad base traversing said shelf on the .side opposite said magnet, said clamp being provided with risers extended from said base along said magnet lengthwise and with retaining-arms to hold the other end of said magnet, said shelf and base being apertured opposite the central bore of said magnet to promote ventilation.

5. An electricarc lamp havinga cylindrical cover and means to suspend the same; a frame comprising a central post having a shelf provided with an annular member; means intermediate said cover and member to enable said cover to sustain said frame; and a springy or cushioned medium intermediate said member and sustaining means.

6. A rider or contact member for the carbone of arc-lamps comprising a cylindrical tube adapted to be seated upon the upper end of said carbon, and provided with current-collecting devices, and means tending normally to press said devices outwardly from the Walls of said rider.

7. A rider or contact member of the class described having current-collecting devices comprising springs secured to the inner walls of said cylinder and tendingnormally to present current-eollecting surfaces beyond the outer walls of said tube.

8. A rider or contact member of the class described having cuWent-collecting devices comprising springs socu red to the inner walls of said cylinder and tending norn'n'tlly to present current-collecting surfaces beyond the outer walls of said tube, said springs being bent back upon themselves from said collecting-surfaces, opposite and in contact with each other and serving mutually each to augment the resiliency of the other and cooperating to conduct the current to the rider.

9. The con'ibination with the clutch-rod of an arc-lamp and a clutch. of the pivoted ring type, of a tension-spring interposed between an arm extended from the clutch-ring beyond its pivot, and a point of supporton the clutchrod, said spring being adapted to take up vi brations of the lamp-fraine and prevent their transmission to said clutch and carbon.

10. The combination with the clutch-rod of an arc-lamp and a clutch of the pivoted ring type, of a tension-spring interposed between an arm extended from the clutch-ring beyond its pivot and a point of support on the clutchrod, said spring being adapted to take up vibrations of the lamp-frame and prevent their transmission to said clutch and carbon; said support being adjustable on said rod to permit said adjustment of said spring.

11. The combination with the carbon-coir trolling mechanism, of an arc-lamp, of a dashpot comprising a stationary plunger provided with air-packing grooves; a cylindrical shell fitting snugly on said plunger, and having vents in its closed end; and a washer and cooperating weight adapted to permit ready assembly of said shell and plunger telescopically and consequent approach of the carbons, but to close said vents and impede separation of shell and plunger, and consequently of the carbons.

12. In an arc-lamp, a head or member of the class described; having a central aperture to permit passage of the upper carbon, a crown portion with an upper attaching-aperture and transverse trimining-passage, said head being adapted to receive hangers or supporting means for the lower carbon.

13. Ahead or memberof the class described provided with a downwardly-extendcd boss arranged co axially with respect to the central carbon-apertu re; combined with a ring, larger in diameter than said boss, and presenting toward the are an annular disk of lava or other suitable insulating and refractory material, and adapted to form, with said ring and boss, a gas-chamber, surrounding the upper carbon.

1 1-. The combination with an arc-lamp havview-opening, of an incandescent lamp sitnposition, substantially as described.

ated adjacent and visible through said view- In testimony whereof I have signed my opening, an adjustable contact member adname to this specification in the presence of 5 jacent the path of the upper carbon in said two subscribing witnesses.

head, and connections between said adjust- JOSEF HENRY HALLBERG.

able contact member, said incandescent lamp Witnesses:

and the leads of said arc-lamp to enable said ALEXANDER O. PROUDFIT,

incandescent lamp to be energized upon the JOHN G. EDWARDS.

ing a head V and a cover provided with a attainment by said carbon ofapredetermined IO 

